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#include <crypto.h>
#include <boost/scoped_ptr.hpp>
#include <botan/botan.h>
#include <botan/hmac.h>
#include <botan/hash.h>
#include <botan/types.h>
namespace {
const char*
getBotanHashAlgorithmName(isc::cryptolink::HMAC::HashAlgorithm algorithm) {
switch (algorithm) {
case isc::cryptolink::HMAC::MD5:
return ("MD5");
break;
case isc::cryptolink::HMAC::SHA1:
return ("SHA-1");
break;
case isc::cryptolink::HMAC::SHA256:
return ("SHA-256");
break;
case isc::cryptolink::HMAC::UNKNOWN:
return ("Unknown");
break;
}
// compiler should have prevented us to reach this, since we have
// no default. But we need a return value anyway
return ("Unknown");
}
} // local namespace
namespace isc {
namespace cryptolink {
class HMACImpl {
public:
explicit HMACImpl(const void* secret, size_t secret_len,
const HMAC::HashAlgorithm hash_algorithm) {
Botan::HashFunction* hash;
try {
hash = Botan::get_hash(
getBotanHashAlgorithmName(hash_algorithm));
} catch (const Botan::Algorithm_Not_Found&) {
isc_throw(isc::cryptolink::UnsupportedAlgorithm,
"Unknown hash algorithm: " + hash_algorithm);
} catch (const Botan::Exception& exc) {
isc_throw(isc::cryptolink::LibraryError, exc.what());
}
hmac_.reset(new Botan::HMAC::HMAC(hash));
// If the key length is larger than the block size, we hash the
// key itself first.
try {
if (secret_len > hash->HASH_BLOCK_SIZE) {
Botan::SecureVector<Botan::byte> hashed_key =
hash->process(static_cast<const Botan::byte*>(secret),
secret_len);
hmac_->set_key(hashed_key.begin(), hashed_key.size());
} else {
hmac_->set_key(static_cast<const Botan::byte*>(secret),
secret_len);
}
} catch (const Botan::Invalid_Key_Length& ikl) {
isc_throw(BadKey, ikl.what());
} catch (const Botan::Exception& exc) {
isc_throw(isc::cryptolink::LibraryError, exc.what());
}
}
~HMACImpl() { }
size_t getOutputLength() const {
return (hmac_->OUTPUT_LENGTH);
}
void update(const void* data, const size_t len) {
try {
hmac_->update(static_cast<const Botan::byte*>(data), len);
} catch (const Botan::Exception& exc) {
isc_throw(isc::cryptolink::LibraryError, exc.what());
}
}
void sign(isc::dns::OutputBuffer& result, size_t len) {
try {
Botan::SecureVector<Botan::byte> b_result(hmac_->final());
if (len == 0 || len > b_result.size()) {
len = b_result.size();
}
result.writeData(b_result.begin(), len);
} catch (const Botan::Exception& exc) {
isc_throw(isc::cryptolink::LibraryError, exc.what());
}
}
void sign(void* result, size_t len) {
try {
Botan::SecureVector<Botan::byte> b_result(hmac_->final());
size_t output_size = getOutputLength();
if (output_size > len) {
output_size = len;
}
memcpy(result, b_result.begin(), output_size);
} catch (const Botan::Exception& exc) {
isc_throw(isc::cryptolink::LibraryError, exc.what());
}
}
std::vector<uint8_t> sign(size_t len) {
try {
Botan::SecureVector<Botan::byte> b_result(hmac_->final());
if (len == 0 || len > b_result.size()) {
return (std::vector<uint8_t>(b_result.begin(), b_result.end()));
} else {
return (std::vector<uint8_t>(b_result.begin(), &b_result[len]));
}
} catch (const Botan::Exception& exc) {
isc_throw(isc::cryptolink::LibraryError, exc.what());
}
}
bool verify(const void* sig, size_t len) {
// Botan's verify_mac checks if len matches the output_length,
// which causes it to fail for truncated signatures, so we do
// the check ourselves
try {
Botan::SecureVector<Botan::byte> our_mac = hmac_->final();
if (len == 0 || len > getOutputLength()) {
len = getOutputLength();
}
return (Botan::same_mem(&our_mac[0],
static_cast<const unsigned char*>(sig),
len));
} catch (const Botan::Exception& exc) {
isc_throw(isc::cryptolink::LibraryError, exc.what());
}
}
private:
boost::scoped_ptr<Botan::HMAC> hmac_;
};
HMAC::HMAC(const void* secret, size_t secret_length,
const HashAlgorithm hash_algorithm)
{
impl_ = new HMACImpl(secret, secret_length, hash_algorithm);
}
HMAC::~HMAC() {
delete impl_;
}
size_t
HMAC::getOutputLength() const {
return (impl_->getOutputLength());
}
void
HMAC::update(const void* data, const size_t len) {
impl_->update(data, len);
}
void
HMAC::sign(isc::dns::OutputBuffer& result, size_t len) {
impl_->sign(result, len);
}
void
HMAC::sign(void* result, size_t len) {
impl_->sign(result, len);
}
std::vector<uint8_t>
HMAC::sign(size_t len) {
return impl_->sign(len);
}
bool
HMAC::verify(const void* sig, const size_t len) {
return (impl_->verify(sig, len));
}
void
signHMAC(const void* data, size_t data_len, const void* secret,
size_t secret_len, const HMAC::HashAlgorithm hash_algorithm,
isc::dns::OutputBuffer& result, size_t len)
{
boost::scoped_ptr<HMAC> hmac(
CryptoLink::getCryptoLink().createHMAC(secret,
secret_len,
hash_algorithm));
hmac->update(data, data_len);
hmac->sign(result, len);
}
bool
verifyHMAC(const void* data, const size_t data_len, const void* secret,
size_t secret_len, const HMAC::HashAlgorithm hash_algorithm,
const void* sig, const size_t sig_len)
{
boost::scoped_ptr<HMAC> hmac(
CryptoLink::getCryptoLink().createHMAC(secret,
secret_len,
hash_algorithm));
hmac->update(data, data_len);
return (hmac->verify(sig, sig_len));
}
} // namespace cryptolink
} // namespace isc
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